Research On The Control Strategy Of Coordinated Grid Connection Of Optical Storage

The potential of PV energy as a green and sustainable resource to replace traditional fossil energy sources is constantly being exploited.However,photovoltaic power generation is affected by many other factors,and directly connecting to the grid will influence the grid,influencing the frequency and voltage stability of the grid,thus causing enormous losses.The research object of this paper is photovoltaic grid-connected,in which an energy storage system is paralleled on the output side of the photovoltaic power generation system to solve the issue of unstable output capacity of the photovoltaic system itself by harmonising the power output between the two systems,and by controlling the grid-connected inverter through the VSG control strategy,so that the system has a similar frequency and voltage adjustment capability as the synchronous generator.Firstly,for more accurate tracking of the maximum power point so that the system has greater robustness,this paper has proposed a P&O-DISMC method to track the maximum power point of the system output by combining the DISMC based on the P&O.The simulation results demonstrate that the P&O-DISMC controller has more accurate tracking capability than other Maximum Power Tracking methods.Secondly,the topology of the energy storage system paralleled on the DC side of the photovoltaic power system is proposed,and the feasibility of coordinated control is tested through simulation to verify the coordinated output of the light storage by simulating changes in external elements such as the light strength.The mathematical model of the VSG is set up,and the Active-Frequency Control and Reactive-Voltage Control of the VSG are analysed,and the feasibility of the control strategy of the VSG is tested by simulation.Finally,to achieve a fast and stable grid connection,a pre-synchronous grid connection control strategy is proposed to regulate the grid-connected system’s frequency,voltage,and phase prior to grid connection.An improved VSG control strategy is proposed to observe grid-connected system action by setting parameter offsets during grid-connected stable operation.The comparison results indicate that the Light Storage Virtual Synchronous Generator system,when grid-connected,can quickly regulate the active output to stabilise the whole when disturbed,and has excellent dynamic performance.Compared with the traditional VSG control system,the improved VSG control system can enable the system to recover stability more quickly.